Treatments

Friday, 18 February 2005 17:36
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Generally speaking, this complex neurogenic pain syndrome is best treated at a specialist pain clinic, with a multidisciplinary approach.

Of the well-established treatment regimes, opiates are frequently used.
However, these may be ineffective in combating any central component of the pain.

The issue of dependency concerns most practitioners and may lead to reluctance to prescribe. It is likely that there will be a risk of physical dependence, and thus of withdrawal symptoms if the opiate medication is discontinued.

Also, there is an element of tolerance that may develop in long- term use, with the need for increasing doses for effective pain relief.

However, psychological dependence and abuse are less likely in chronic pain patients than in those who use opiate drugs recreationally.

It is best to start with short-acting morphine four hourly, until adequate analgesia is established. Breakthrough pain may require top-up doses.

Once control has been established, it is advisable to change to a slow release preparation such as MS Continus, which has a predictable duration of action for 8-12 hours, and can thus be given twice daily.

Fluctuations in dose requirement may occur, and in this case, the slow-release preparation should be replaced with a shorter acting one for the period of increased dose requirement.

Adjunctive treatment may also be necessary:

Antidepressants are useful for the background burning neuropathic pain, but are used in far lower doses than for depression (e.g. amitriptyline 25mg at night).

It should be noted that the more selective antidepressants such as Prozac have been found to be poorly effective against neuropathic pain, first generation tricyclics being much more useful.

Anticonvulsants such as carbamazepine are particularly useful for the sharp, lancinating type of neuropathic pain. A relatively new drug, Neurontin (Gabapentin) is useful for pain relief and muscle spasms.

Antiarrythmic drugs such as mexiletine may also be used for neuropathic pain.

Muscle relaxants may be needed, including benzodiazepines such as diazepam.

Baclofen is a useful drug for spasticity. However, it should be noted that paradoxical increase in spasticity might occur.

Also the Committee for Safety of Medicines (CSM) has advised that serious side-effects such as autonomic dysreflexia may be seen on withdrawal and a gradual dose reduction over at least 1-2 weeks should be undertaken to avoid these. ([i])

Non-steroidal anti-inflammatory drugs are not generally effective for pain relief and may cause significant gastrointestinal side effects and occasionally kidney problems after prolonged use.

Some patients have found that the troublesome nocturnal muscle cramps may be relieved by quinine.


[i] British National Formulary  Number 35 (March 1998)